1. Field of the Invention
The present invention relates to a substrate processing apparatus for processing a substrate, and to a substrate transport method for transporting a substrate. Examples of the substrate to be processed include semiconductor wafers, substrates for liquid crystal display devices, substrates for plasma display devices, substrates for FED (Field Emission Display) devices, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks and substrates for photo masks.
2. Description of Related Art
In production processes for a semiconductor device and a liquid crystal display device, a substrate processing apparatus of a single substrate processing type is often used, which is adapted to process a single substrate (a semiconductor wafer or a glass substrate for the liquid crystal display device) at a time (see, for example, US2008/0159832A1 and US2008/0199284A1).
A substrate processing apparatus disclosed in US2008/0159832A1 includes, as shown in FIG. 16 of the present application, an indexer block B1 and a processing block B2 which are arranged in juxtaposition. The indexer block B1 includes a carrier holder CH and an indexer robot IR1. The processing block B2 includes eight processing units U and a main robot MR1. The eight processing units U include two sets of four vertically stacked processing units U, which are disposed on opposite sides of a substrate transport passage. In FIG. 16, the uppermost two processing units U are shown. A substrate platform PASS for retaining substrates W is disposed at a junction between the indexer block B1 and the processing block B2.
The carrier holder CH is adapted to hold carriers C which each accommodate a plurality of substrates W. The carriers C are held by the carrier holder CH in alignment in a predetermined alignment direction.
The indexer robot IR1 is adapted to transfer the substrates W between any of the carriers C and the substrate platform PASS. The indexer robot IR1 is disposed adjacent the carrier holder CH. The indexer robot IR1 is movable along the carrier alignment direction.
The main robot MR1 is adapted to transport the substrates W between the substrate platform PASS and any of the processing units U. The main robot MR1 is disposed in the transport passage.
In the substrate processing apparatus disclosed in US2008-0159832A1, a substrate processing operation is performed, for example, in the following manner. First, an unprocessed substrate W is taken out of any of the carriers C, and transferred to the substrate platform PASS by the indexer robot IR1. Then, the unprocessed substrate W transferred to the substrate platform PASS is taken out of the substrate platform PASS, and loaded into any of the processing units U by the main robot MR1. The substrate W processed in the processing unit U is unloaded from the processing unit U and transported to the substrate platform PASS by the main robot MR1. Then, the processed substrate W is transferred from the substrate platform PASS into any of the carriers C by the indexer robot IR1.
On the other hand, a substrate processing apparatus disclosed in US2008/0199284A1 includes, as shown in FIG. 17 of the present application, an indexer block B1, a first processing block B2a and a second processing block B2b which are arranged in juxtaposition. The indexer block B1 includes a carrier holder CH and an indexer robot IR1. The first processing block B2a includes eight processing units U and a first main robot MR1. The second processing block B2b includes eight processing units U and a second main robot MR2. A first substrate platform PASS1 is disposed at a junction between the indexer block B1 and the first processing block B2a. A second substrate platform PASS2 is disposed at a junction between the first processing block B2a and the second processing block B2b.
The eight processing units U of the first processing block B2a include two sets of four vertically stacked processing units U, which are disposed on opposite sides of a transport passage. Similarly, the eight processing units U of the second processing block B2b include two sets of four vertically stacked processing units U, which are disposed on opposite sides of the transport passage. A total of 16 processing units U of the first and second processing blocks B2a, B2b are three-dimensionally arranged, and disposed alongside the transport passage as seen in plan.
In the substrate processing apparatus disclosed in US2008-0199284A1, a substrate processing operation is performed, for example, in the following manner. First, an unprocessed substrate W is taken out of any of the carriers C, and transferred to the first substrate platform PASS1 by the indexer robot IR1. Then, the unprocessed substrate W transferred to the first substrate platform PASS1 is taken out of the first substrate platform PASS1, and loaded into any of the processing units U of the first processing block B2a by the first main robot MR1. The substrate W processed in the processing unit U of the first processing block B2a is unloaded from the processing unit U, and transported to the first substrate platform PASS1 by the first main robot MR1. Then, the processed substrate W is transferred from the first substrate platform PASS1 into any of the carriers C by the indexer robot IR1.
Alternatively, the unprocessed substrate W transferred to the first substrate platform PASS1 by the indexer robot IR1 is further transferred to the second substrate platform PASS2 by the first main robot MR1. Then, the unprocessed substrate W transferred to the second substrate platform PASS2 is taken out of the second substrate platform PASS2, and loaded into any of the processing units U of the second processing block B2b by the second main robot MR2. The substrate W processed in the processing unit U of the second processing block B2b is unloaded from the processing unit U, and transported to the second substrate platform PASS2 by the second main robot MR2. Then, the processed substrate W transported to the second substrate platform PASS2 is transferred from the second substrate platform PASS2 to the first substrate platform PASS1 by the first main robot MR1. Then, the processed substrate W is transferred into any of the carriers C from the first substrate platform PASS1 by the indexer robot IR1.
It is conceivable to increase the number of the processing units in order to increase the throughput of the substrate processing apparatus (the number of substrates processed in a unit period). Where a plurality of processing units are provided, these processing units should be arranged vertically and/or horizontally. Where the processing units are vertically arranged, however, the substrate processing apparatus has an increased height. This may make it impossible to install the substrate processing apparatus in a clean room. Therefore, where a multiplicity of processing units are provided, these processing units should be arranged not only vertically but also horizontally.
In the substrate processing apparatus disclosed in US2008/019928A1, for example, the 16 processing units U, which are greater in number by eight than those provided in the substrate processing apparatus disclosed in US2008/0159832A1, are arranged three-dimensionally and disposed alongside the substrate transport passage as seen in plan. In the substrate processing apparatus disclosed in US2008/0199284A1, however, a longer period is required for substrate transportation by the first main robot MR1, and influences the overall substrate processing period required for the substrate processing operation to be performed by the substrate processing apparatus. This prevents improvement of the throughput of the substrate processing apparatus.
More specifically, as described above, the first main robot MR1 performs a substrate transportation operation for transporting the substrate W between the first substrate platform PASS1 and any of the processing units U, and a substrate transportation operation for transporting the substrate W between the first substrate platform PASS1 and the second substrate platform PASS2. Therefore, the total substrate transportation period required for the substrate transportation operations to be performed by the first main robot MR1 is greater than a substrate transportation period required for substrate transportation by the main robot MR1 of the apparatus disclosed in US2008/0159832A1. Therefore, the substrate transportation period required for the substrate transportation operations to be performed by the first main robot MR1 influences the overall substrate processing period required for the substrate processing operation to be performed by the substrate processing apparatus, and prevents the improvement of the throughput of the substrate processing apparatus.
Further, the two main robots provided in the substrate processing apparatus disclosed in US2008/0199284A1 are expensive, thereby increasing the costs of the substrate processing apparatus.
It is also conceivable to design the substrate processing apparatus such that the first main robot MR1 can be moved horizontally along the transport passage in order to obviate the substrate transportation between the first substrate platform PASS1 and the second substrate platform PASS2 by the first main robot MR1. This makes it possible to obviate the second main robot MR2 and the second substrate platform PASS2. With this arrangement, however, time is required for horizontally moving the first main robot MR1 along the transport passage when the substrate W is transported between the first substrate platform PASS1 and each of the processing units U, thereby increasing the substrate transportation period required for the substrate transportation by the first main robot MR1. Therefore, the substrate transportation period required for the substrate transportation by the first main robot MR1 influences the overall substrate processing period required for the substrate processing operation to be performed by the substrate processing apparatus, thereby preventing the improvement of the throughput of the substrate processing apparatus.